Chapter 10 Computing plant height

10.1 Introduction

Plant height is not very well simulated for the moment. It is computated using the plant width, which depends itself on the plant lai (lai+eai+laisen). Please see Chapter 2 for more details. Figure 10.1) shows the simulated height of wheat in Auzeville, and the variables from which it is computed.

Simulated height compared to the observed values, and variables from which it is computed from, in a self-intercrop of Wheat-Wheat

Figure 10.1: Simulated height compared to the observed values, and variables from which it is computed from, in a self-intercrop of Wheat-Wheat

The plant height is important in the case of intercrops because it has high impact on the light interception of both species. Indeed, a sensitivity analysis was performed using the sticRs package on the parameter that links the lai to the height: P_rapforme. The results are shown below (see html version of this book for interactivity):

height_sensi= sticRs::load_sensi(dirpath = "data/rapforme_sensitivity")
if(knitr:::pandoc_to() == "html") {
  gg_objects= 
    lapply(height_sensi$gg_objects, 
           function(x){
             plotly::ggplotly(x, tooltip= "group")
           })
  htmltools::tagList(gg_objects)
}else{
  multiplot(plotlist = height_sensi$gg_objects)
}

As we can see on the above plots, as the plant height is affected, its lai is also impacted afterwards. We can also see that no values of P_rapforme gave satisfactory plant height, so maybe the link between the plant lai and the plant height is not as straightforward as previously thought, and maybe there is another variable that could be better correlated to it.